'\" te
.\" Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
.\" Copyright 1989 AT&T
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.TH FREEB 9F "Jan 16, 2006"
.SH NAME
freeb \- free a message block
.SH SYNOPSIS
.LP
.nf
#include <sys/stream.h>



\fBvoid\fR \fBfreeb\fR(\fBmblk_t *\fR\fIbp\fR);
.fi

.SH PARAMETERS
.sp
.ne 2
.na
\fB\fIbp\fR\fR
.ad
.RS 6n
Pointer to the message block to be deallocated. \fBmblk_t\fR is an instance of
the \fBmsgb\fR(9S) structure.
.RE

.SH INTERFACE LEVEL
.sp
.LP
Architecture independent level 1 (DDI/DKI).
.SH DESCRIPTION
.sp
.LP
The \fBfreeb()\fR function deallocates a message block. If the reference count
of the \fBdb_ref\fR member of the \fBdatab\fR(9S) structure is greater than
\fB1\fR, \fBfreeb()\fR decrements the count. If \fBdb_ref\fR equals \fB1\fR, it
deallocates the message block and the corresponding data block and buffer.
.sp
.LP
If the data buffer to be freed was allocated with the \fBesballoc\fR(9F), the
buffer may be a non-STREAMS resource. In that case, the driver must be notified
that the attached data buffer needs to be freed, and run its own freeing
routine. To make this process independent of the driver used in the stream,
\fBfreeb()\fR finds the \fBfree_rtn\fR(9S) structure associated with the
buffer. The \fBfree_rtn\fR structure contains a pointer to the driver-dependent
routine, which releases the buffer. Once this is accomplished, \fBfreeb()\fR
releases the \fBSTREAMS\fR resources associated with the buffer.
.SH CONTEXT
.sp
.LP
The \fBfreeb()\fR function can be called from user, interrupt, or kernel
context.
.SH EXAMPLES
.LP
\fBExample 1 \fRUsing \fBfreeb()\fR
.sp
.LP
See \fBcopyb\fR(9F) for an example of using \fBfreeb()\fR.

.SH SEE ALSO
.sp
.LP
.BR allocb (9F),
.BR copyb (9F),
.BR dupb (9F),
.BR esballoc (9F),
.BR free_rtn (9S)
.sp
.LP
\fIWriting Device Drivers\fR
.sp
.LP
\fISTREAMS Programming Guide\fR
